option Prefix for needsPackage and friends instead of FileName

[mahrud]

I wave my fist at the sky every time I have to laboriously type

needsPackage("PkgName", FileName => ".../PkgName.m2")

I mean, the whole /PkgName.m2 part is unnecessary (not to mention FileName ...)

Solution: add option Prefix that accepts a directory and deprecate FileName (i.e. still accept it but maybe don't mention it in the documentation).

[mikestillman]

I would be happy with such a change, I also find it painful to type all that in! Prefix seems like a good solution...

[mahrud]

Would you like to implement it?